easy cheesy spinach and ham quiche

Ingredients For easy cheesy spinach and ham quiche

• 1 can

  (10 ounces) sliced mushrooms or 1 cup fresh sliced mushrooms
• 1 c

  onion, chopped
• 1 pkg

  (10 ounces) frozen spinach, thawed and excess water squeezed out.
• 1/3 c

  mayonnaise
• 1/3 c

  milk
• 4

  eggs
• 1 c

  cheddar cheese, grated
• 3 oz

  finely chopped ham
• 1

  deep dish pie shell
• 1/4 c

  parmesan cheese, grated